Case reports of patients with EV have been reviewed. It has been determined that EV is an autosomal recessive disease, accompanied in at least 10% of cases by mental retardation. Flat warts occur in all patients, pityriasis-like warts in 75% of cases. Cancer of the skin develops in 1/3 of cases. Relationship of mutant gene to viral oncogenesis and mental retardation is unknown.